1. Field of the Invention
This invention relates to tape carriers utilized in the tape automated bonding of leads to semiconductor chips, such as integrated circuits, and more particularly to such tape carriers which are suitable to be used in the molding of semiconductor chips into a resinous mold after the inner bonding of the leads on the chips.
2. Description of the Prior Art
Conventionally, the electrical connections of the electrodes of semiconductor chips, such as integrated circuit elements, to outer circuits have been effected by means of outer leads of a package which are bonded to the electrodes of the chips trough thin bonding wires. In recent years, however, wireless bonding methods have been developed and are replacing the wire bonding method in an increasingly wide areas of applications as methods of making electrical connections of the electrodes of the chips to outer circuits.
The tape automated bonding method of the semiconductor chips is one of the most promising among the wireless bonding methods of the electrodes of the chips. FIGS. 1(a) and (b) of the drawings show a conventional tape carrier utilized in the tape automated bonding process. The flexible tape-shaped film 1 has formed therein repeating patterns of apertures 2 and 4 (a pattern only is shown in the figure). Further, patterns of leads are formed on a surface of the film 1 so that each pattern of leads 6 surrounds the central aperture 2, extending approximately in a direction perpendicular to the sides of the aperture 2. Semiconductor chips 3 are bonded to the leads 6 in the inner lead bonding process at the inner lead portions 6a thereof by means of the bumps 3a, i.e., projecting electrodes for the bonding of the chips. In certain applications, the semiconductor chips 3 thus carried by the tape 1 are put in a transfer molding press and sealed into a resinous mold or package together with predetermined portions of the leads 6.
The conventional tape carrier shown in FIG. 1 has following disadvantages when utilized in the molding of the chips. Namely, the fine patterns of leads 6 are subjected to severe stress during the molding process due to the fact that the clamping force of the molding dies of the molding press exerted on the leads and those portions of the film 1 that are situated in the cavity of the molding device is mainly born by the leads 6 which are less flexible and more resistant to mechanical pressure than the film 1. Thus, the thin leads 6 may easily be deformed during the molding process.